Terry Young fuels a solar car that made a 2,600-mile cross-country trip earlier this year. Solar energy provided barely one-tenth of 1 percent of U.S. electricity in 2012.

Written by

Dennis G. Hall

Back when I was a graduate student in the early 1970s, I spent a year at the University of Arizona's Optical Sciences Center. It was an exciting time to be studying about light. The laser, first demonstrated in 1960, was still a new and wondrous thing.

The laboratory I worked in that year pursued two bold visions of the future. One imagined laser light carrying vast streams of data through thin strands of highly transparent glass. The other imagined sunlight generating clean electricity for a growing population. Skeptics preferred cheaper approaches - the existing copper wire-based ...